Cursor moving across the spreadsheet and wiping out lines

[Guest]

I was working on a spreadsheet and the cursor started moving across the
spreadsheet wiping out whatever was typed in its path. It stopped but when I
tried to put something in the boxes it went through I couldn't.

 

[Guest]

Sounds to me like you had hit the 'Insert' button, which would put you into
overwrite mode. As for the rest of what you said...

Simply need more details to even guess on that one...